TW508458B - Micro-tunable filter structure design suitable for various spectrum - Google Patents

Abstract

The present invention provides a micro-tunable filter structure design suitable for various spectrum, which comprises: a silicon substrate for silicon-on-insulator (SOI); a silicon oxide insulation layer to separate the silicon substrate for silicon-on-insulator into the front side and back side of silicon wafer; a floating mechanical structure which comprises a thin-plate structure and at least a narrow, long support pin, the first terminal of the at least one narrow, long support pin is connected to the thin plate, the second terminal of the at least one narrow, long support pin is connected to a fixed region; a separating block connected to the fixed region and the positive side of silicon wafer; an air gap formed between the floating mechanical structure and the surface of the positive side of the silicon wafer, the starting distance of the air gap is determined by the height of the separation block; a first mirror fabricated at the center of the thin plate; a floating electrode fabricated on the thin-plate structure, the floating electrode is electrically connected to the exterior through the at least one narrow, long support pin and the fixed region; a fixing electrode fabricated on the surface of the positive side of the silicon wafer right under the floating electrode, and spaced with the floating electrode by the air gap; a V-groove of resonant cavity fabricated on the positive side of the silicon wafer located right under the first mirror, the planar bottom of the V-groove of resonant cavity exposes the silicon oxide insulation layer on the silicon substrate for silicon-on-insulator; at least an anti-sticking V-groove fabricated on the positive side of the silicon wafer and located under the at least one narrow, long support pin; and a back side groove fabricated on the back side of the silicon wafer and aligned to the first mirror, the planar bottom of the back side groove exposes the silicon oxide insulation layer on the silicon substrate for silicon-on-insulator; and the second mirror fabricated on the planar bottom portion of the back-side groove.

Description

No. j 9Q1Q 卯 Rfi V. Description of the invention (1) Field of invention 91 · 6.28 The revised version of Maoming is about a frequency-adjustable optical filter TOF (Tunable Optical Filter, 4 persons Λ.?) About using a microfabrication technology to design your micro-FM optical filter structure. [Description of Known Techniques] The common FM optical filter is based on the principle of Fabry-Perot interferometer (FP interferometer for short). Electrical material modulation) Optical resonant cavity (Resonant Cavity), when the length of the resonant cavity satisfies a specific half of the wavelength ^ wavelength AG m / 2 (m represents the order), the output light pulse has a very narrow FWHM (FWHM Full Width of Half Max um) is widely used in optical communication and various spectrum detection equipment. See Figure 1 for the basic characteristics of the FP interferometer light output. In order to better understand the problems that its design may face, the following will discuss some basic theories of the FP interferometer. One is the adjustable spectral range FSR (Free Spectral Range); the other is the resolution% of a specific light wave (Resol-ving Power), which represents the spectral distribution width △ () ratio of the center wavelength and half intensity of the output light wave. The relationship between these two and other manufacturing inflammation numbers is expressed as follows: / (1) FSR ^ xlilrifd

'• 28508458 Case No. 90109966 V. Description of the invention (2) iR =

Ail〇 (\ -R) 中 where 0 is the center wavelength of the output light wave; d is the distance between the two mirrors; nf = 1: the refractive index of the fluid (usually air) inside; the reflectivity of the r mirror. B ^ = FP interferometer usually requires a large adjustable FSR and i output; long angles are just high. However, ′ can be given by the formulas = and ⑺ = 2: ΐΐ2 takes into account both. The formula (2) is inversely proportional to d, while the resolution of formula (2) is directly proportional to d. In other words, if 广 广 围 ’, the obtained individual wavelength resolution will be more compromised than the traditional F ° P. Take an example of the interferometer specifications used in optical communications: among them. = 1.5 rhyme, nfd = i〇Ca, V /-, T -3 ° 0, 〇〇0 ^ Δ ^ 〇〇5π, >, the value 逖 is less than the current requirements for high density wavelength multiplexing in optical communications) ' Represents very good spectral resolution. However, its range is only about 0.1 nm, so even the conventional Fp interference: good spectral analysis characteristics, but using traditional processing techniques and groups, it is not possible to produce an F p interferometer with wide-spectrum spectral characteristics. . The use of the conventional FP interferometer is quite inconvenient, mainly because two shovels = parallelism adjustment difficulty #, and the difficulty of manufacturing is high, which makes: The door is used to solve the above problems. In recent years, the FM optical filter based on the Fp interferometer originally made using micromachining technology 508458 91. 6. 28 _ Case No. 90109966 _ year and month __ 5. Description of the invention (3) Wave device T 0 F Its application is developing rapidly, please see: (Annex l) Jerman, JHet al ·, A miniature Fabry-Perot interferometer fabricated using silicon micromachining techniques, Solid-State Sensor and Actuator Workshop, 1988 · Technical Digest ·, IEEE, 1988, Page (s): 16 -18 (Annex 2) Raley, NFet al ·, A Fabry-Perot microinterferometer for visible wavelengths Solid-State Sensor and Actuator Workshop, 1992.

5th Technical Digest., IEEE, 1 9 9 2, Page (s): 170 -173 (Annex 3) Aratani, K. et al., Process and design considerations for surface micromachined beams for a tuneable interferometer array in silicon, MEMS, 93, IEEE., 1993

(Annex 4) Zavracky, PMet al ·, Miniature Fabry Perot spectrometers using mi cromach ini ng technology WESCON / '95 · Conference record., 1995, Page (s): 325 (Annex 5) Vail, EC et a 1., GaAs micromachined widely tunable Fabry-Perot filters, Electronics Letters, Volume: 31, Issue: 3, 2 Feb. 1995, Page (s): 228 -229 (Annex 6) Zhu, ZH et a 1., Surface micromachined long wave length LED / photodetector with a continuous tuning range of 75 nm, MEMS? 97, Page (s): 61 -65 (Annex 7) Peerlings, J. eta 1., GaA s / A 1 As micromachined tunable Fabry-Perot filters for dense wave length

Page 7 508458 Case No. 90109966 91. 6 :, _Ά Amendment V. Description of Invention (4) division multiplex systems, 11th International Conference on Optical Communications, Volume: 3, 1997, Page (s): 1 -5 (Annex 8 ) Viktorovitch, P. et al., Tunable microcavity based on III -V semiconductor micro-opto-electromechanical structures (MOEMS) with strong optical confinement, IEEE / LEOS Summer Meetings, 1 9 9 8, Page (s): 63-64 (Annex 9) Greek, S. et a 1., Mechanical considerations in the design of a micromechanical tuneable I nP-based WDM filter, Microelectromechanical Systems, Journal of, Volume: 8 I ssue: 3, Sep. 1 999, Page ( s): 328 -334 (Annex 10) Goossen et a 1., Micromechanical Modulator, US. Patent No. 5, 50 0, 76 1. (Annex ll) Jourdain et al ·, Tunable Fabry-Perot Interferometer with Floating Electrode on One Mirror and Control Electrode Pair on Opposing Mirror, US. Patent No. 6, 078, 395 (Annex 12) Tayebati, Electrically Tunable Optical Filter Utilizing a Deformable Multi-Layer Mirror, US. Patent No. 5,739, 945. (Payment 13) Koskinen, Infrared Detector with Fabry-Perot Interferometer, US. Patent No. 5, 589, 689

Page 8 508458 91. 6. 28 _ Case No. 90109966_Year_Ifi__ V. Description of the Invention (5) (Annex 14) Blomberg et al., Electrically Tunable Fabry-Perot Interferometer Produced by Surface Micromechanical Techniques for Use in Optical

Material Analysis, US · Patent No. 5, 561, 523 The advantage of a miniature FM optical filter is that it is produced or assembled using a semiconductor process to obtain a fine pitch d (which is usually between 10 μm), which is found by formula (1) This action makes it possible to widen the spectral range that can be adjusted. For example, the same as the above application example, just changing nfd from 10 mm to 1 um, the modulation range can be increased to 1000 nm. As a result, it has a spectrometer function equivalent to Grating spectrometry, which cannot be achieved by traditional Fp interferometers, and is also the biggest feature of miniature FM optical filters. ... However, the above-mentioned literature and invention still have many shortcomings to be improved. In the case of using bulk processing technology (Bulk Micromachining) and silicon wafer bonding (Wafer Bonding), the unevenness of the surface of the two bonded wafers will affect the bonding yield and the parallelism between the mirrors. The larger distance between two wafers (> 5um) will increase its static electricity and dynamic voltage. At the same time, the bonded substrate effect (silicon wafer) limits the use of the wavelength range (for example, it cannot be used for visible light). 】 Surface Micromachining can not be used to make a large optical resonator (d < 3um). Even if the adjustable 2 spectral range is large, good light wave analysis I cannot be achieved, which limits its & J column such as optical communication DWDM), in addition, the substrate effect also limits the use of the producer using the GaAs stupid crystal method, at the same time, the optical resonator is also limited, the method is more complicated 508458 month amendment No. 90109966 V. Description of the invention (6) The disadvantages similar to the surface micro-machining method. (a) Wide and infrared In view of this, making an FM optical filter with a wide modulation range at the same time, (b) high light wave resolution, (c) low driving power, limited by the substrate effect, (d) suitable for The design and fabrication of microstructures in various spectral bands (such as the dragon and the stern line) are the sights of the present invention. [Summary of the Invention] Therefore, the present invention = mesh & '(A) See wide modulation range, (b) High light wave solution_pre-filtering (c) Low driving voltage, and not limited to substrate effect, (d) Applicable to long-term spectral bands (visible light, infrared, etc.) Microstructure design. A kind of implementation mode according to the present invention relates to a structure of a miniature FM optical filter suitable for various spectrums, including a silicon insulating layer silicon substrate (SO I), a silicon oxide insulating layer, and a silicon insulating layer. The silicon substrate is divided into a front surface and a two-sided wafer; a suspension mechanical structure including a 4-plate structure and at least one slender foot, and the first end of the at least one slender foot, The second end of the at least one slender foot connected to the thin plate is connected to a fixed area; a partition block connects the fixed area to the front surface of the wafer; an air gap is formed in the suspension machine The starting distance of the air gap between the structure and the front surface of the Shi Xi wafer is determined by the height of the partition; a first reflector is made in the center of the thin plate structure; a floating electrode I is made on the slab structure The floating electrode is electrically connected to the outside through the at least one slender leg and the fixed area. The fixed electrode is made on the front side; the surface of the wafer is located below the floating electrode jade and is connected to the floating electrode. & aE is away from the air gap; a cavity ¥ -shaped groove is made in the front silicon 508458 91. 6. 28

------ 90109966 V. Description of the invention (7) The wafer is located directly below the first reflector, and the flat bottom of the v-shaped groove of the resonant cavity exposes the oxidation located in the middle of the silicon insulating layer silicon substrate. A silicon edge layer; at least one anti-stick ν-type groove made in the front silicon wafer, bit = directly below the at least one slender leg; and a back groove made in the back silicon wafer, Directly aligned with the first reflector, the flat bottom of the back groove is exposed—the silicon oxide insulating layer in the middle of the silicon insulating layer silicon substrate; and a reflector is made on the flat bottom of the back groove . [Explanation of the embodiment] In order to improve the shortcomings of the above documents and inventions, the present invention will propose a new FM filter to improve it. Referring to Fig. 2a, it is a sectional view of the structure of the embodiment of the present invention, and Fig. 2b is an exploded view of the three-dimensional structure of Fig. 2a. Including: providing a silicon substrate, the silicon substrate 10 is a silicon insulating layer silicon wafer (SilicONn)

Insulator (S0I), the silicon substrate 10 has a silicon oxide insulating layer i00b in the middle. The silicon substrate 10 is divided into a front silicon wafer 100c (also called a device wafer) and a back silicon wafer 100a. (Also known as Handle Wafer);-suspension mechanical structure 200, an air gap 50 1 from the surface of the front silicon wafer i00c. The suspension mechanical structure 200 includes a thin plate structure 201, four slender legs 203, and four supporting and fixing areas 204. The first end point 20 3a of the slender leg 203 is connected to the thin plate 201, and the second end point 203b of the slender leg 203 is connected to the fixed area 204. The fixed area 204 is connected through a The spacer 103a (Spacer) is connected and fixed on the surface of the front silicon wafer 100c. The thickness of the spacer 103a is the beginning of the air gap 501.

508458 H'l __Case No. 90109966 V. Description of the invention (8) The modified moving electrode 20 2 is fabricated on the thin plate structure 201, and is connected to the fixed area 204 through an elongated leg 203 for electrical connection with the outside world; A fixed electrode 1 〇1 is fabricated on the surface of Shixi wafer 1 00c on the front side, and its position is directly below the floating electrode 2 0 2; a plurality of V-shaped grooves 5 0 0, 5 0 2 are fabricated on the front side 100 c. The silicon wafer includes a resonant cavity v-shaped groove 500 located below the first reflecting mirror 400, and an anti-sticking V- located below the elongated foot 2003. V-shaped groove 502, resonant cavity V-shaped groove 500 square flat bottom exposed silicon oxide insulating layer 丨 〇b located in the middle of the silicon substrate 10; and a back V-shaped groove 50 3 made on the reverse silicon wafer In 100a, the first reflecting mirror 400 is aligned, the square flat bottom of the V-shaped groove 503 on the back surface exposes the silicon oxide insulating layer 丨 00b located in the middle of the silicon substrate 10; and a first Two reflecting mirrors 300 are manufactured on the square flat bottom of the V-shaped groove 503 on the back surface. I = The optical resonant cavity of the FM optical filter of the present invention is a first reflecting mirror 400 fabricated on a thin plate structure 201, and a square flat bottom of the resonant cavity v-type :: Cao 500 (connected to The two-mirror optical τ (Λ 发 Λ optical cavity length d) formed by the second mirror 30 °) 'on the back of the v-shaped concave _ is combined with the surface microfabrication technology (Xi Si sacrificial layer technology) And the size of the micro-machining technology (etching), the thickness of the optical cavity 〃 air gap 501 and the thickness of the wafer IOc and 100C, this thickness can be used by the V user who is the front stone Evening wafers have the same specifications (0.3 ~ 10-, so it is quite capable of achieving a balance of 14 through the appropriate grip of 100c thickness, and achieving a balance between the spectral resolution to achieve the aforementioned optical modulation range ... Get broad spectral tone

508458 91. 6. 28 --- Case No. 9010 Liyang _ year month day ___ V. Description of the invention (9) The variable range can also meet the spectral characteristics of optical resolution. By designing and manufacturing the floating electrode 202 and the fixed electrode 101, the length of the optical resonant cavity between the first reflector 400 and the second reflector 300 can be adjusted by means of electric field attraction. The floating electrode 2 The distance 501 between the 〇2 and the fixed electrode 101 is defined by the production of the sacrificial layer and the subsequent etching operation. Therefore, different gaps 501 can be defined according to different needs. Because the pitch is defined by the thickness of the sacrificial layer, which is usually <3um, it only needs a lower voltage to adjust the length of the optical cavity (compared to the aforementioned wafer bonder). Anti-stick V-shaped groove 5 0 2 is made under the slender foot 203 to avoid mutual adhesion between the slender foot and the bottom front silicon wafer. The surface tension caused by the etching liquid Sticking.

In addition to the above advantages, the first mirror 400 and the second mirror 300 have excellent parallelism (this cannot be overcome by conventional technology wafer bonders). In addition, the special microstructure design of the FM filter is not limited to the effect of the substrate 10 effect, and it can be manufactured only by selecting the materials of the first reflecting mirror 400 and the second reflecting mirror 300. FM filters suitable for various bands (for example: visible light, infrared, etc.). These above advantages are not supported by the aforementioned literature or the inventor (see attachment). S will be shown in the following section. The manufacturing sequence explains the manufacturing of the FM filter element in the embodiment shown in FIG. 2a. (1) As shown in FIG. 3a, first, a substrate 10 is provided with a silicon insulating layer silicon wafer (S0I) in a crystal direction. The structure of the silicon insulating layer includes: front silicon wafer I00c (element silicon wafer), oxygen α… 508458 fifth, description of the invention (10) 10 0b and reverse wafer 100a (set silicon wafer) ). Among them, the thickness of 100c is at least larger than lum and the thickness of 100b is between 0.3 and 0.5um, and the thickness of 100a is between 300 and 400um. A fixed electrode 1 (n) is produced on the wafer 100: surface definition, and the manufacturing method of the fixed electrode 101 is impurity doping by high temperature diffusion or ion implantation. (2) As shown in FIG. 3b 'Deposit an insulating layer 1 02 on the surface of the front Shi Xi wafer 1 00c' The material is silicon nitride or silicon oxide, with a thickness between 〇 · 丨 ~ 〇 ·. And define a part of the insulating layer 10 removed 2. In order to form a predetermined v-shaped groove etching window lj2a and 102b. Among them, 102a is an etching window of a predetermined resonant cavity v-shaped groove 50 (), and 102b is a predetermined anti-sticking Etching window of V-shaped groove 5 0 ° (3) As shown in FIG. 3c, a polycrystalline silicon material 103 is deposited on the surface of the wafer 10, and the thickness is between 0.5 and 3 um. The deposition method is to use Low-Pressure Chemical Vapour Deposition LPCVD. The polycrystalline stone material 103 can be used as two parts. One is as a sacrificial layer material 1 forming a suspended sheet 201 and an elongated leg 203. 〇3b (removed in the subsequent etching process); the second is to connect the surface of the front silicon wafer 100c Spacer layer 103a fixed to the suspension mechanical structure 200 (the diagram shown in FIG. 2a is only used to represent the structure of the embodiment, and cannot represent the proportion of the inter-dimensional size. In this embodiment, the fixed area 2 The area of 〇4 is larger than the area of the thin plate structure 201, so after the sacrificial layer 103b is etched and removed, the spacer layer 103a can still be retained to connect and fix the surface of the wafer with the fixed area 204. (4) Such as As shown in Fig. 3d, a mechanical structure 200 'is deposited on the polycrystalline stone material 103 surface, and the mechanical structure is defined as a fixed area 204 and an elongated leg area.

Page 14 508458 tlife 90109966 9L 28 said Amendment 5. Description of the invention (11) Domain 203 and thin plate structure 201. The recess 200a defined in the center of the thin plate structure 201 will be used to define the 400 area of the first mirror, and its position is aligned with the etched window of the V-shaped groove of the 102a resonant cavity. The mechanical structure 200 is a sandwich structure composed of three layers of materials, namely silicon-rich silicon nitride 200a (Silicon Rich Nitride), polycrystalline silicon 200b, and silicon-rich silicon nitride 200c. Among them, silicon-rich silicon nitride has fairly good mechanical rigidity and relatively low thermal residual stress (see Annex 15 Bruce CS Chou et al., A method of fabricating low-stress dielectric thin film for microsensors applications, IEEE Electron Device Letters 18, 1 9 9 7, p. 5 9 9-6 0 1 ·), so it is most suitable as a micro-mechanical structure with high quality and high stability. The polycrystalline silicon 2 0 b located in the middle serves as a conductive material for the mechanical structure and the floating electrode 2 2 at the same time. (5) As shown in FIG. 3e, the first reflecting mirror 400 is manufactured at the position of the aforementioned recess 20a, and the reflecting mirror 400 is made of a multi-layer dielectric material with high reflection and low loss. Reflector. The basic composition unit of a multilayer dielectric layer is a pair of dielectric materials with a high refractive index and a low refractive index, which is usually Ti% / Si02. Its thickness ΐ satisfies n t = in / 4 respectively, where n is the refractive index and in is the center wavelength of the modulated spectrum. (6) As shown in the figure, the surface of the front wafer 10 is protected by a mechanical fixture. The anisotropic etching solution is removed from the back of the silicon substrate 10 corresponding to the bottom of the first mirror 400. Part of the backside silicon wafer 100 and the material until it contacts the middle oxidized stone to form another back surface [the bottom surface of the V-shaped groove 50 exposed by the bottom of the concave groove 503, the second flat surface forms a second = The structure and materials of the mirror 3 0 0 '3 0 0 are the same as those of the front mirror, _white ", and the fan-mirror 1 mirror 40 0 is the same, and it is not repeated here. Finally, it is presented through mechanical mechanism f ---, m ^ Bao 蠖Silicon wafer 100a

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Page 15 2 b

Case No. 901099fifi V. Description of the invention (12) The surface 'separates the sacrificial layer 103b with fragmented anisotropy to form a gap 501', and the etching solution will simultaneously remove the polycrystalline silicon 102a wafer and form an Asia-Pacific * After the predetermined last name engraving window u, several V-shaped concave samples 50Πfen ηο are defined to define the final component company, P | 3 &amp; 丨 ^ 孓 groove bUO and 502, branch station-taxi The eight RR structures I, and D are sectional views shown in FIG. 2a. Yi and Shan Shan Cup. The characteristics of Gan Yue are shown in Figure 4, which is the driving voltage between the floating electrode 2 0 2 and the fixed electrode 桎], and the vertical axis is earlier + ^ There are 101 types of unresolved poles, which represent ramming, ancient and different from different wavelengths (frequency). Specifications of the FM filter. Thousands of waves are lost. The first mirror in the center of the center is straight. The area of the structure 201 is 220mm. The width is 15um, 10 == 0um, and the length of the slender legs is about ^. Mirror 40. And 30 = two are ‘air gaps 501 3⑽ and 8 pairs of T i 02 / S i 02 dielectric film, the thickness of A / 4 are respectively i 74 rhyme 26 2 electric shell ^

The flat area with high reflectivity at 99.5% covers WOW). From the results in Figure 4 of Figure 4, it can be found that only a voltage of about 5 volts is needed, and the spectral range of the modulation can reach ~ 80 nm (the spectral resolution is as high as 800,000). This result is quite suitable for the use of DWDM for visual communication. ). The description of the examples is only for the convenience of explaining the technical content of the present invention, and not to limit the present invention to the above embodiments in a narrow sense. It is made without exceeding the scope of the present invention and the following patent applications. The various variations of Pycnogenol are still within the scope of the present invention. For example, the above-mentioned embodiment of the mirror Ti 〇 2 / SiO 2 material is mainly used in the near-infrared range L of optical communication. However, the special structure of the present invention can be used as other if it is matched with other spectral optical plating and design. Application, for example: MgF2 / T i 〇? The material selection can be used in the 3 ~ 5um band for gas detection (such as co c〇2, etc.) ° Furthermore, the production of the back V-shaped groove 503 can also be made by inductor Coupled electricity

Page 16 No. 508458 No. 901Q9% ft Rev. V. Invention Description (13) 椠 Reactive Ions | Insect Carved (referred to as Inductiveiy coupled plasma ICP RIE, for example: Alcatel 601E), in reverse silicon wafer 100a The formed vertical tube wall u-shaped trenches are replaced. Explanation of symbols 10 Silicon insulation layer Silicon substrate 100a Backside silicon wafer 100b Silicon oxide insulation layer 100c Front wafer 101 Fixed electrode 102 Insulation layer 102a Resonant cavity V-shaped groove 102b Anti-stick V-shaped groove 103 Polycrystalline Material 103a polycrystalline silicon spacer layer [pin 103b polycrystalline silicon sacrificial layer area 200 suspension mechanical structure 20 0a polycrystalline silicon nitride 20 0b polycrystalline polycrystalline silicon 2 0 0c thin silicon structure 201a thin plate Structure center 4 20 2 Floating electrode 203 Slim feet 203a Slim feet and sheet

Page 17 508458 91. 6. 28 _ Case No. 90109966 _ month and year _ V. Description of the invention (14) 2 0 3 b Connection point between the slender foot and the fixed area 2 0 4 Fixed area of the suspension mechanical structure 3 0 0 Second Mirror 40 0 First reflector 5 0 0 Resonant cavity V-shaped groove 501 Air gap 5 0 2 Anti-stick V-shaped groove 5 0 3 Back V-shaped groove

Page 18 508458 9ί · 6, 23. _Case No. 90109966_year month _ «_ Brief description of the figure Figure 1 shows the basic characteristics of the optical output of the FP interferometer. FIG. 2a is a structural sectional view of an embodiment of an FM optical filter according to the present invention. FIG. 2b is an exploded view of the three-dimensional structure of FIG. 2a. 3a to 3f show the manufacturing sequence of the cross section of FIG. 2a. FIG. 4 is a result data diagram of the embodiment of FIG. 2a. %

Page 19

Claims (1)

508458 δΐ 6. 28 _Case No. 90109966_ Modification of Year of the Month_ VI. Application for Patent Scope 1. A structural design of a miniature FM filter suitable for various spectrums, including: a silicon insulating layer silicon substrate (SO I), using a The silicon oxide insulating layer divides the silicon insulating layer substrate into two front and back wafers. A suspension mechanical structure includes a thin plate structure and at least one elongated leg. The first end point is connected to the thin plate structure, and the second end point of the at least one elongated leg is connected to a fixed area; A partition connected between the fixed area and the front silicon wafer; an air gap formed between the suspension mechanical structure and the front silicon wafer surface; the initial distance of the air gap is determined by the height of the partition; A first reflector is made in the center of the sheet structure; a floating electrode is made on the sheet structure; the floating electrode is electrically connected to the outside through the at least one elongated leg and the fixed area; a fixed electrode is made in The front silicon wafer surface is directly below the floating electrode, and is spaced from the air electrode by the air gap; A resonant cavity V-shaped groove is made in the front silicon wafer and is located directly below the first reflector. The square flat bottom of the resonant cavity V-shaped groove exposes the silicon oxide in the middle of the silicon insulating silicon substrate An insulating layer; at least one anti-stick V-shaped groove, made in the front silicon wafer, directly under the at least one slender leg; a back groove, made in the back silicon wafer, directly aligned with the A first reflector, the flat bottom of the back groove exposes the silicon oxide insulating layer in the middle of the silicon insulating layer silicon substrate; and Page 20 A mirror is manufactured by Xibei. ： 2: A correction meter, in which the front side of the Xixi wafer is weighed; the structure of the micro-FM filter in 4 is at least 1 micron. It is a single crystal silicon wafer with a crystal orientation of (10). The thickness is 3 ° as described in the patent scope of ShenJin, in which the structure of the stone oxide insulation, micro / frequency wave ferrule is provided. The thickness is between 0.3 and 0.5 microns. The thickness of the structure of the micro-FM filter described by Dou Zhongxi members; the two-circle system is the single crystal direction (1 °°) ... 5 · As mentioned in the patent scope of the patent, where the suspension machine η The structure of the past and the description of the miniature FM filter is Shi Xi and Fu Shi Xi nitride nitride Xi :::: The materials are sequentially Fu Shi Xi nitride nitride Xi, and more "6. For example, apply for a patent | Γ = The third, Meiji structure. Design, in which the structure of the floating electric 'mini miniature FM filter is designed 7. If the application for the special material is polycrystalline. The structure of the ^ -type FM filter described in the solid item is set to δ. For example, the scope of the patent application for a single crystal silicon meter on the surface of a 1S silicon wafer, wherein the structure of the miniature FM wave waver described in the sub-parameter is set to silicon) . The material of the ghost is polycrystalline silicon or amorphous silicon (amorphous 9 · such as Shen Jing patented ribs, plan ′ where the back n ::; the structure of the micro-frequency filter structure slot is made of stone anisotropy VI Counted on page 21, where the first-item / micro-FM filter structure is set with the transmission coefficient dielectric material :: inverse f J is composed of multiple pairs of high refractive index / low fold 10. The local reflectivity mirror. 508458 91. 6. 28 Page 22